Many agricultural activities are highly time sensitive, with costs and returns being dependent upon a rapid turnover of crops or upon being first to market. Therefore, rapid plant growth is an economically important goal for many agricultural businesses that grow high-value crops such as vegetables, berries, and bananas, as well as for the greenhouse and nursery industry. The importance of improved crop production technologies has magnified as observations have indicated that yields for many well-developed crops have tended to plateau in recent years. The goal of rapid plant growth has been addressed in numerous studies of plant regulatory mechanisms, which remain incompletely understood. In particular, a complete understanding has not been attained for the plant regulatory mechanisms that coordinate carbon and nitrogen metabolism, which must have a major impact on plant growth and development.
Similarly to the desire for rapid plant growth, other plant factors are important to the agricultural industry including factors such as: length of time until seed germination, uniformity of germination, i.e., nearly simultaneously germination, yield, and the ratio of total seed germination.
U.S. Pat. No. 5,922,649 by Pehu et al. illustrates application of a composition, specifically a glycine betaine composition, to improve the yield of plants.
U.S. Pat. No. 6,831,040 by Unkefer et al. illustrates application of prolines such as 2-hydroxy-5-oxoproline, 5-oxoproline (2-pyrrolidone-5-carboxylic acid) and mixtures thereof to plants can promote growth. Maintaining an effective concentration of either or both 2-oxoglutaramate and pyroglutamate in a plant is highly desirable. Elevation of the concentration of the 2-oxoglutaramate can result in improved performance, quality traits and other benefits. Treating plants with 2-oxoglutaramate or pyroglutamate can provide these benefits. To date, methods aimed at maximizing the benefits of pyroglutamate have generally required regular, frequent treatments to maintain the desired levels of the compound.
The present inventors made an extensive investigation of compositions including L and D isomers of pyroglutamate in various ratios and the efficacy of such compositions in promoting seed germination, plant growth and yield. The inventors have found preferred or optimal compositions for promoting such plant growth and yield.